From f4a66d24771f98ddade345d434a7eab0a57c4fc4 Mon Sep 17 00:00:00 2001
From: Lioncash <mathew1800@gmail.com>
Date: Mon, 17 Sep 2018 00:53:38 -0400
Subject: [PATCH] data_processing_bitfield: Move datasize variables after
 early-exit conditionals

Moves the declaration of datasize to the scope that it's used within.
This also takes the opportunity to apply const where applicable, and
make early-exits all vertically consistent with one another.
---
 .../impl/data_processing_bitfield.cpp         | 73 +++++++++++--------
 1 file changed, 44 insertions(+), 29 deletions(-)

diff --git a/src/frontend/A64/translate/impl/data_processing_bitfield.cpp b/src/frontend/A64/translate/impl/data_processing_bitfield.cpp
index 9ca50e9b..06da72e6 100644
--- a/src/frontend/A64/translate/impl/data_processing_bitfield.cpp
+++ b/src/frontend/A64/translate/impl/data_processing_bitfield.cpp
@@ -15,64 +15,79 @@ static IR::U32U64 ReplicateBit(IREmitter& ir, const IR::U32U64& value, u8 bit_po
 }
 
 bool TranslatorVisitor::SBFM(bool sf, bool N, Imm<6> immr, Imm<6> imms, Reg Rn, Reg Rd) {
-    size_t datasize = sf ? 64 : 32;
+    if (sf && !N) {
+        return ReservedValue();
+    }
 
-    if (sf && !N) return ReservedValue();
-    if (!sf && (N || immr.Bit<5>() || imms.Bit<5>())) return ReservedValue();
+    if (!sf && (N || immr.Bit<5>() || imms.Bit<5>())) {
+        return ReservedValue();
+    }
 
-    u8 R = immr.ZeroExtend<u8>();
-    u8 S = imms.ZeroExtend<u8>();
-    auto masks = DecodeBitMasks(N, imms, immr, false);
-    if (!masks) return ReservedValue();
+    const u8 R = immr.ZeroExtend<u8>();
+    const u8 S = imms.ZeroExtend<u8>();
+    const auto masks = DecodeBitMasks(N, imms, immr, false);
+    if (!masks) {
+        return ReservedValue();
+    }
 
-    auto src = X(datasize, Rn);
+    const size_t datasize = sf ? 64 : 32;
+    const auto src = X(datasize, Rn);
 
     auto bot = ir.And(ir.RotateRight(src, ir.Imm8(R)), I(datasize, masks->wmask));
     auto top = ReplicateBit(ir, src, S);
 
     top = ir.And(top, I(datasize, ~masks->tmask));
     bot = ir.And(bot, I(datasize, masks->tmask));
-    X(datasize, Rd, ir.Or(top, bot));
 
+    X(datasize, Rd, ir.Or(top, bot));
     return true;
 }
 
 bool TranslatorVisitor::BFM(bool sf, bool N, Imm<6> immr, Imm<6> imms, Reg Rn, Reg Rd) {
-    size_t datasize = sf ? 64 : 32;
+    if (sf && !N) {
+        return ReservedValue();
+    }
 
-    if (sf && !N) return ReservedValue();
-    if (!sf && (N || immr.Bit<5>() || imms.Bit<5>())) return ReservedValue();
+    if (!sf && (N || immr.Bit<5>() || imms.Bit<5>())) {
+        return ReservedValue();
+    }
 
-    u8 R = immr.ZeroExtend<u8>();
-    auto masks = DecodeBitMasks(N, imms, immr, false);
-    if (!masks) return ReservedValue();
+    const u8 R = immr.ZeroExtend<u8>();
+    const auto masks = DecodeBitMasks(N, imms, immr, false);
+    if (!masks) {
+        return ReservedValue();
+    }
 
-    auto dst = X(datasize, Rd);
-    auto src = X(datasize, Rn);
+    const size_t datasize = sf ? 64 : 32;
+    const auto dst = X(datasize, Rd);
+    const auto src = X(datasize, Rn);
 
-    auto bot = ir.Or(ir.And(dst, I(datasize, ~masks->wmask)), ir.And(ir.RotateRight(src, ir.Imm8(R)), I(datasize, masks->wmask)));
+    const auto bot = ir.Or(ir.And(dst, I(datasize, ~masks->wmask)), ir.And(ir.RotateRight(src, ir.Imm8(R)), I(datasize, masks->wmask)));
 
     X(datasize, Rd, ir.Or(ir.And(dst, I(datasize, ~masks->tmask)), ir.And(bot, I(datasize, masks->tmask))));
-
     return true;
 }
 
 bool TranslatorVisitor::UBFM(bool sf, bool N, Imm<6> immr, Imm<6> imms, Reg Rn, Reg Rd) {
-    size_t datasize = sf ? 64 : 32;
+    if (sf && !N) {
+        return ReservedValue();
+    }
 
-    if (sf && !N) return ReservedValue();
-    if (!sf && (N || immr.Bit<5>() || imms.Bit<5>())) return ReservedValue();
+    if (!sf && (N || immr.Bit<5>() || imms.Bit<5>())) {
+        return ReservedValue();
+    }
 
-    u8 R = immr.ZeroExtend<u8>();
-    auto masks = DecodeBitMasks(N, imms, immr, false);
-    if (!masks) return ReservedValue();
+    const u8 R = immr.ZeroExtend<u8>();
+    const auto masks = DecodeBitMasks(N, imms, immr, false);
+    if (!masks) {
+        return ReservedValue();
+    }
 
-    auto src = X(datasize, Rn);
-
-    auto bot = ir.And(ir.RotateRight(src, ir.Imm8(R)), I(datasize, masks->wmask));
+    const size_t datasize = sf ? 64 : 32;
+    const auto src = X(datasize, Rn);
+    const auto bot = ir.And(ir.RotateRight(src, ir.Imm8(R)), I(datasize, masks->wmask));
 
     X(datasize, Rd, ir.And(bot, I(datasize, masks->tmask)));
-
     return true;
 }